Hong Kong’s incandescent skyline of colorfully illuminated buildings may be the city’s most distinctive calling card. But researchers at the University of Hong Kong say they’re fueling an unwelcome phenomenon: so-called “light pollution.”

In a wide-ranging study of the city’s light pollution, scientists collected data at 18 monitoring stations for three years, and found that the worst readings—at the city’s much-touristed harborfront in Tsim Sha Tsui—clocked numbers some 1,200 times in excess of international standards. Even rural areas and the city’s wetlands experienced light pollution, says Dr. Jason Pun, who led the study.

“There are only two kinds of places in Hong Kong: very bright and a little bright,” he said. In the past decade, he says, as skyscrapers have erected more dazzling, flashing LED panels, the problem has gotten worse.

Just ask web designer Wesley Wai, who for nine years lived in a Mongkok apartment that at times felt like a disco club, with bright lights strobing into his bedroom until dawn. In 2009, he was inspired to make a film capturing the phenomenon, which he says kept him sleepless on numerous nights, despite his attempts to use curtains to keep the light of nearby neon signs out.

In Mongkok—a noisy, dense neighborhood north of Tsim Sha Tsui—the sound and smog of buses and cars can feel oppressive. “But the light was most annoying,” says Mr. Wai, who has since moved away to a quieter neighborhood. “At midnight, the sound wouldn’t be so bad, but the lights were still there.” He recalls that in the year before he made his video, there were three acid attacks on his street that left passersby injured. “I think that kind of environment can turn people crazy,” he says.

Not everyone feels similarly about the city’s lights. In a government-commissioned survey published in 2011, more than 70% of 2,700 respondents said they felt there was light pollution in Hong Kong, but 78% of residents also said lights helped promote tourism and beautify the environment. Another 87% said they believed such illumination—which can make streets feel as bright as noon, even at midnight—have helped maintain the city’s low crime rate.

For years, environmental advocates have called on the government to regulate light in the city, saying it can disturb the nocturnal rhythms of certain wildlife, as well as human sleep patterns. Part of what fuels light pollution is the style of Hong Kong’s neighborhoods, in which commercial and residential developments are heavily mixed. Accordingly, activists say the government—which last year released voluntary guidelines suggesting businesses try to “avoid over-illumination” of their properties—needs to adopt legislation to help people get a better night’s sleep.

“In Hong Kong, people cannot use noisy machines after a certain hour,” says Edwin Lau Che-feng of nonprofit Friends of the Environment. “We also need an ordinance to control light, which creates a nuisance for peoples’ bedrooms.”

On Tuesday, Environmental Secretary Wong Kam-sing said light pollution is an issue the city needs to further address, and that potential plans to do so would be released in a matter of months. Measures could include requiring that lights be turned off during certain hours, he said.

“We perhaps think that brilliant lights that illuminate the ‘Pearl of the Orient’ reflect a prosperous outlook, but with the passage of time, things change,” he said. Decreasing the amount of wattage the city uses, he said, would also have an environmental payoff.